Cocaine abuse continues to be a substantial medical and social problem in the USA and elsewhere. Despite increasing knowledge of the pharmacological basis of cocaine's effects and of the environmental and socio- economic factors in drug abuse, relatively little attention has been given to the cognitive factors that are involved in addiction. It is proposed that a substantial cognitive component of human addiction is a dysexecutive loss of control, that is, an inability to control one's own behavior in light of the strong motivation to consume drug. Our previous research has identified specific executive processes and their corresponding functional neuroanatomy that are compromised in cocaine users. Specifically, anterior cingulate and right dorsolateral prefrontal hypoactivity have been observed for response inhibition and error detection tasks in active cocaine users. As these structures are central to the cognitive control of behavior, their dysregulation may result in an inordinate influence of habits or environmental cues on behavior. A series of studies are proposed that will investigate the functional consequences of compromised cognitive control. The guiding hypothesis is that the anterior cingulate, a structure involved in monitoring one's behavior, is a core neurobiological deficit in cocaine users. As this structure is thought to initiate the involvement of other prefrontal structures central to implementing cognitive control, we propose that these prefrontal "deficits" may be secondary to the cingulate deficit. A further major aim of the proposed research is to assess the persistence or amelioration of cognitive dysfunctions following drug abstinence. The proposed research will assess the executive neurofunctioning of cocaine users at the start and end of a one-year period of abstinence. Tasks will include measures of inhibitory control, error detection, adaptive control (i.e., behavioral flexibility) and attentional control (i.e., being able to ignore cocaine stimuli). The research will also assess if dysfunction in these processes is predictive of relapse or ameliorates with abstinence. [unreadable] [unreadable] [unreadable]